The hamlet of Middle Island is located as its name implies in the middle of Long Island (the first largest island in the United State), in the town of Brookhaven. It is bounded on the west by Coram, on the west by Ridge, and on the north by Rocky Point. Middle Country Road (also known as Route 25), its main commercial thoroughfare, runs through it.

Its history goes back to 1766, when the first Presbyterian church was built, with Rev. David Rose as pastor. He also pastored the South Haven church, and was an interesting figure as he covered his immense parish on horseback. His saddle bags were filled with Bibles and medicines, as he was also a doctor. In 1837, the present church was built just to the rear of the other one, and served the community for 200 years until the new Christian Education building was built at Longwood in 1966. The old church is the home of the Middle Island Christian Fellowship. The first schoolhouse, built in 1813, stood just east of the church. Across the road from the church is the cemetery opened in 1766 and incorporated in 1869. In 1960, it was renamed the Union Cemetery Association of Middle Island. Its oldest stone is that of Daniel Brewster who died in 1748.

For over 100 years, Pfeiffer's store was in operation, and was the typical country store, supplying nearly all the wants of the people for miles around. Farmers brought in their butter and eggs, and traded them for groceries and other supplies. The country store carried besides groceries, dry goods, men's and women's clothing boots and shoes (felt boots were popular), paint, hardware, crockery, feed and fertilizer, and almost anything one could think of. In the back room hung smoked hams and bacon, and the salt pork barrel, the molasses barrel, vinegar barrel etc. The country store and post office were the meeting place for everyone. Men and boys socialized around the old pot-bellied stove, playing checkers, etc. In April 1971, the old store was burned down by the local firemen so the new owners could build a gas station. This began the transition from a farming community to an urban development.

Artist Lake used to be called Corwin's Pond, because Rev. Corwin lived nearby He was one of the first pastors of the Wading River Congregational Church, organized in 1785, and the first pastor of the New Village (Centereach) Congregational Church in 1815. The artist, Alonzo Chappel lived east of Artist Lake, where K-Mart now stands, from 1869 until his death in 1887. Chappel's paintings of historic American scenes appeared as illustrations in many books. Artist Lake was named in anticipation that other artists would follow Chappel and settle there.

The old Ashton homestead on the East Bartlett Road was the home of an American major during the Revolution, and they had interesting events to relate. Prosser's Cathedral Pines is located on the road to Yaphank and is the largest white pine forest on Long Island The oldest trees were planted by "Uncle Billy" Dayton in 1812, and the property is now part of the Suffolk County Parks and open to the public daily. Carman's (formerly called Connecticut) River used to rise in Pfeiffer's Pond in Middle Island and flow down through Yaphank and into the Great South Bay at Brookhaven. Several mills were located on this river.